Energy loss, chipping resistance, and abrasion resistance of polymeric materials such as rubber materials are important physical quantities that can affect various properties of products formed from these materials. For example, in the case of tires as rubber products, the energy loss is closely related to fuel economy and grip performance, while the chipping resistance and abrasion resistance are closely related to the life of the tires.
As a method for evaluating energy loss in a polymeric material, a technique of measuring the loss tangent (tan δ) by dynamic viscoelasticity measurement is widely used (see Patent Literature 1). However, this technique causes great errors, and its measurement accuracy is insufficient. Another problem is that in the case where differences between samples are small, such differences cannot be evaluated with good reproducibility.
As a method for evaluating chipping resistance or abrasion resistance of a tire, for example, a road test is commonly performed in which the incidence of chipping of a tire tread portion or the groove depth is measured after driving a predetermined distance. However, since such a method requires building of a tire and long-distance driving, there is a demand for an efficient evaluation method that provides measurement in a short period of time and at low cost. Yet, such an efficient method for evaluating chipping resistance is generally unknown.
Further, a Lambourn abrasion test and DIN abrasion test are known as the method for evaluating abrasion resistance in a short period of time and at low cost. However, these methods cause great errors, and their measurement accuracy is insufficient although some degree of correlation is found between results of these tests and road test results. Another problem is that in the case where differences between samples are small, such differences cannot be evaluated with good reproducibility (see Non patent Literature 1).